Orthopedic Systems for Spine and Tracking Control

ABSTRACT

An orthopedic implant system includes an intervertebral implant. The implant includes a body having an upper surface extending generally in a first plane. The upper surface has a first plurality of longitudinal grooves and a second plurality of transverse grooves extending therealong. Portions of the upper surface extend between adjacent longitudinal grooves and transverse grooves form individual peaks. A lower surface extends generally in a second plane, parallel to the first plane. The lower surface has a third plurality of longitudinal grooves and a fourth plurality of transverse grooves extending therealong. Portions of the lower surface extend between adjacent longitudinal grooves and transverse grooves form individual peaks.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from U.S. Provisional PatentApplication Ser. No. 61/715,891, filed on Oct. 19, 2012, which isincorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention generally relates to an orthopedic systems fortreatment of the spine specifically intervertebral implants, containingmechanism to rigidly attach to the vertebrae and systems for full lotcontrol traceability.

BACKGROUND OF THE INVENTION

Anterior intervertebral interbody fusion is a common technique fortreating degenerative disc disease and major deformity. The anteriorapproach is common for both the cervical (ACIF) and lumbar (ALIF) spine.The approach allows full visibility of the disc and fusion site, whileminimizing disruptions to the branch nerves of the spinal column as wellas major trauma to the posterior musculature. Typical intervertebralfusion consists of an interbody spacer and a fixation means, such asanterior plate or posterior pedicle screws. An objective of theinterbody spacer is to maintain the height of the intervertebral space,but allow for bone to grow through the interbody spacer to form a fusedmass between vertebrae.

Typically the interbody spacers are constructed from inert biocompatiblematerial such as titanium or polyether-ether-ketone (PEEK). Titanium istypically used in orthopedic systems due to its strength andosteoconductive properties. However, in intervertebral spacers, titaniumis not the preferred choice due to its high stiffness compared withbone. The large stiffness differential between bone and titanium hascaused a high incidence of subsidence of the implant into the vertebralbody. This has led the way for other biomaterials being selected for thespacer's body material. PEEK is a common interbody material selectedbecause the Young's Modulus is extremely similar to bone and thematerial is extremely inert. However, PEEK is not an osteoconductivematerial and a large central oval cavity is the only space designed forbone through growth, thus the spacers remove a larger percentage of thefusion area.

Current orthopedic systems used to treat conditions in the anteriorspine have started to incorporate plate fixation directly to theinterbody (see, for example, US2009/0182430). These systems typicallyutilize specifically designed plates to interbody connections and do notgive a large amount of flexibility in the operating room for the enduser to interoperatively switch between a standalone interbody and anisolated interbody. In addition, the interbodies used in the standaloneassemblies are constructed of the same inert material and do not allowfor bone ingrowth to occur. The lack of fusion area increases thestrength of the fixation required to maintain the construct rigidityduring healing.

In July 2012, the United States (US) Food and Drug Administration (FDA)announced it was in the process of enacting rules to meet thecongressional mandate for every medical device to contain a UniqueDevice Identification (UDI), such as lot number and part numbers. The USmandate requires every permanently implantable medical device to containfull traceability from manufacturer through distribution. This includessmall devices that lack sufficient surface area to contain adistinguishable UDI. Typically, only sterile products have the abilityto include a traceability sticker or manual lot recording is requiredfor non-sterile products.

BRIEF SUMMARY OF INVENTION

In accordance with one exemplary embodiment of invention, anintervertebral implant includes an upper surface generally conforming toa plane and lower surface generally conforming to a plane. A series oflongitudinal grooves located on both upper and lower planes and a seriesof transverse grooves form a peak. A generally centrally located cavitypierces the upper and lower planes and surfaces. The implant furthercontains the means to contain a permanent osteoconductive material onall peaks on both the upper and lower planes.

In a second exemplary embodiment of the invention, an intervertebralimplant includes an upper surface generally conforming to a plane andlower surface generally conforming to a plane. A centrally locatedthreaded aperture for adaption to an insertion instrument. A secondcentrally located recess is configured in a rectangular shape to preventrotation of mating mechanisms.

In a third exemplary embodiment of the invention, an insertioninstrument includes a handle attached a hollow cylindrical tube attachedto an engagement end. The engagement end contains a fastener forsecuring to an implant which can be activated by activating a cam. Theengagement end containing a positive stop for controlling the depth anddistance of the implant.

In a fourth exemplary embodiment of the invention, an implant includes aplate designed to cooperatively attach to the intervertebral implantwith an engagement mechanism. The engagement mechanism having agenerally rectangular shape is located on the posterior plane of theimplant and extending from the plane. A locking screw is designed tocooperatively attach to the plate implant and secure the intervertebralimplant to a fixed position.

In a fifth exemplary embodiment of the invention, an implant includes aplate, adaptable to an intervertebral implant, and bone screws, wherethe bone screws contain cantilever segments. The cantilever segmentsdeform during insertion of the bone screws into a recess. The recessgenerally containing a cylindrical section, an undercut and a roundseat, with the undercut preventing the cantilever segments from backingout after insertion.

In a sixth exemplary embodiment of the invention, a removable implantbody extension contains descriptive information regarding the implant.The descriptive information contains lot number and/or serial number ofthe connected implant, allowing removal of the body extension to aid intracing the implant. The removable body extension is adaptable forsingle cycle sterilization or multiple cycle sterilization.

In a seventh exemplary embodiment of the invention, a bone screwcontains a distal thread and a proximal thread connected by a shaft.Where the distal thread contains a distal pitch and the proximal screwcontains a proximal pitch with the distal pitch being greater than theproximal pitch.

BRIEF DESCRIPTION OF THE DRAWINGS

Other aspects, features, and advantages of the present invention willbecome more fully apparent from the following detailed description, theappended claims, and the accompanying drawings in which like referencenumerals identify similar or identical elements.

FIG. 1 is a perspective view of an intervertebral implant in accordancewith one exemplary embodiment of the invention;

FIG. 2 is a top view of the implant of FIG. 1;

FIG. 3 is a front view of the implant of FIG. 1;

FIG. 4 is a side view of the implant of FIG. 1;

FIG. 5 is a rear view of the implant of FIG. 1;

FIG. 6 is a cross section view of the intervertebral implant of FIG. 1,showing a hole configuration;

FIG. 7 is a side view of the implant of FIG. 1 with a first alternativeexemplary type of surface;

FIG. 8 is a side view of the implant of FIG. 1 with a second alternativeexemplary type of surface;

FIG. 9 is a micrograph showing distribution of titanium on a PEEKsubstrate, providing an illustrative exemplary composition of theinvention;

FIG. 10 is a perspective view of an alternative exemplary embodimentview of an insertion instrument;

FIG. 11 is an enlarged perspective view of an insertion instrument ofFIG. 10, engagement end;

FIG. 12( a) is a cross section view of the insertion instrument of FIG.10, showing the attachment mechanism;

FIG. 12( b) is an enlarged truncated cross section view of the insertioninstrument implant attachment of FIG. 10;

FIG. 13 is an enlarged axial view of the insertion instrument of FIG.10, showing visualization of the alignment features;

FIG. 14 is a top of view of the insertion instrument of FIG. 10;

FIG. 15 is a perspective view of a plate for attachment to anintervertebral implant of FIG. 1, in accordance with one exemplaryembodiment of the invention;

FIG. 16 is a side view of the implant of FIG. 15;

FIG. 17 is a perspective view of a plate's posterior side showingrectangular connection of the plate shown in FIG. 15;

FIG. 18 is a perspective view of the plate shown in FIG. 15, attached tointervertebral implant of FIG. 1, with attachment mechanism;

FIG. 19 is a side cross section view of the plate and intervertebralimplant assembly of FIG. 18, showing connection means;

FIG. 20 is a top cross section view of the plate and intervertebralimplant assembly of FIG. 18, showing connection means;

FIG. 21 is a perspective view of a fully configured plate andintervertebral implant, shown in FIG. 18, with bone screws, inaccordance with another exemplary embodiment of the invention;

FIG. 22 is a side view of the fully configured plate and intervertebralimplant assembly of FIG. 21;

FIG. 23 is a perspective view of a fifth exemplary embodiment, showing abone screw with cantilever segments;

FIG. 24 is a truncated cross section view of the bone screw shown inFIG. 23, inserted into the plate shown in FIG. 15, in a non-lockedstate;

FIG. 25 is a truncated cross section view of the bone screw of FIG. 23,inserted into the plate shown in FIG. 15, in a locked state;

FIG. 26 is a perspective view of a sixth exemplary embodiment, showing abone screw with removable body extension;

FIG. 27( a) is a side view of a bone screw with removal body extensionshown in FIG. 26, showing descriptive information;

FIG. 27( b) is a further rotated side view of a bone screw with removalbody extension shown in FIG. 26, showing descriptive information;

FIG. 28 is a cross section view of bone screw with removal bodyextension shown in FIG. 26;

FIG. 29 is a side view of a removal body extension showing descriptiveinformation;

FIG. 30 is a perspective view showing the removable body extension ofFIG. 29, attached to the plate shown in FIG. 15;

FIG. 31 is a perspective view of a sixth exemplary embodiment, showing abone screw;

FIG. 32 is another perspective view of the bone screw shown in FIG. 31;

FIG. 33 is another side view of the showing a bone screw shown in FIG.31;

FIG. 34 is a top view showing the bone screw of FIG. 31;

FIG. 35 is a cross sectional view showing the bone screw shown in FIG.31;

FIG. 36 is an enlarged view of the proximal end of the bone screw shownin FIG. 31;

FIG. 37 is an enlarged view of the shaft of the bone screw shown in FIG.31; and

FIG. 38 is an enlarged view of the distal end of the bone screw shown inFIG. 31.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the drawings, like numerals indicate like elements throughout.Certain terminology is used herein for convenience only and is not to betaken as a limitation on the present invention. For purposes of thisdescription, the terms “anterior”, “posterior”, “superior” and“inferior” describe the position of surfaces or features relative to theanatomy. The term “anterior” refers to features having a relativeposition toward the front side of a spine, and “posterior” refers tofeatures having a relative position toward the rear side of the spine.The term “superior” refers to features having a relative position aboveother features, in the cranial direction, and the term “inferior” refersto features having a relative position below other features in a caudaldirection. The terminology includes the words specifically mentioned,derivatives thereof and words of similar import.

The embodiments illustrated below are not intended to be exhaustive orto limit the invention to the precise form disclosed. These embodimentsare chosen and described to best explain the principle of the inventionand its application and practical use and to enable others skilled inthe art to best utilize the invention.

Reference herein to “one embodiment” or “an embodiment” means that aparticular feature, structure, or characteristic described in connectionwith the embodiment can be included in at least one embodiment of theinvention. The appearances of the phrase “in one embodiment” in variousplaces in the specification are not necessarily all referring to thesame embodiment, nor are separate or alternative embodiments necessarilymutually exclusive of other embodiments. The same applies to the term“implementation.”

As used in this application, the word “exemplary” is used herein to meanserving as an example, instance, or illustration. Any aspect or designdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other aspects or designs. Rather, use ofthe word exemplary is intended to present concepts in a concretefashion.

Additionally, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or”. That is, unless specified otherwise, or clearfrom context, “X employs A or B” is intended to mean any of the naturalinclusive permutations. That is, if X employs A; X employs B; or Xemploys both A and B, then “X employs A or B” is satisfied under any ofthe foregoing instances. In addition, the articles “a” and “an” as usedin this application and the appended claims should generally beconstrued to mean “one or more” unless specified otherwise or clear fromcontext to be directed to a singular form.

Applicant has observed a number of problems with the existingintervertebral spacers which use unsuitable materials, such as titaniumor Polyether-ether ketone (PEEK). Interbody cages constructed from rigidmaterials such as titanium tend to have a large Young's modulus in therange of 105-130 GPa compared to bone, which has a relatively lowmodulus of 1.8 GPa. This makes titanium at least 58 times stiffer thanbone and clinical studies have concluded this as the main cause ofsubsidence within the vertebral endplates. Subsidence is where theimplant breaks through the vertebral endplates and intervertebralspacing is lost. Subsidence has been linked to pseudo-arthrosis,non-unions and re-operations of the fusion site. The high materialstiffness may also enhance stress shielding of the central graftpreventing or delaying bone through growth. However, the surface oftitanium is well known for its osteoconductive properties.Osteoconductive materials encourage cell adhesion to the surface and canact like bone itself. This property can be used to increase the fusionarea and allow bone growth directly on the implant.

The other well utilized material for intervertebral spacers is PEEK.PEEK is a semicrystalline thermoplastic with excellent mechanical andchemical resistance properties that are retained to high temperatures.In intervertebral fusion, intervertebral spacers constructed from PEEKhave found a growing usage due to their relatively low stiffness,approximately 3.6 GPa compared to 1.8 GPa for bone. Clinical literaturehas reported lower occurrences of subsidence with PEEK intervertebralspacers, compared to a titanium spacer. However, PEEK is not anosteoconductive material and as such placement of a PEEK spacer withinthe intervertebral disc space can reduce the fusion area 60-70%, thuslowering the chances of a full fusion.

The intervertebral spacers of the present invention improve upon priorapproaches by addressing the subsidence and settling of the endplates,while maximizing the fusion area. The various embodiments of the presentinvention allow proper load distribution through the use of lowstiffness material enabling the load to transfer through the bone graftmaterial during implant settling, while increasing the fusion area andreducing the mitigation risks. To accomplish this, the embodimentsinclude an osteoconductive material, such as titanium, applied on asubstrate with similar properties to bone. The inferior and superiorsurfaces are configured to maximize the surface area through the use ofa rectangular pyramid shaped tooth. The assembly also includes amechanism which can engage both an insertion instrument and supplementalhardware, such as a plate and screw assembly.

Referring now to FIG. 1, an interbody spacer 100 in accordance with oneexemplary embodiment of the invention is shown. Interbody assemblies inaccordance with the present invention may include a variety of body andteeth configurations. Interbody spacer 100 includes a rigid body 111 anda plurality of peaks, or teeth, 112 which form rigid body 111.

Rigid body 111 has an anterior surface 113 and a posterior surface 114that is generally parallel to the anterior surface. Anterior surface 113has a larger external surface area than posterior surface 114. Anteriorand posterior surfaces 113, 114, respectively, are joined by a pair oflateral side surfaces 115 that extend generally radially to one another.A superior end surface 116 extends generally in a first plane and aninferior end surface 117 extends generally in a second plane obliquely,in a non-parallel manner, to the first plane between anterior sidesurface 113 and posterior side surface 114. Superior and inferior endsurfaces 116, 117, respectively, taper or converge toward one another asend surfaces 116, 117 extend toward posterior side surface 114, forminga wedge-shaped structure. The anterior, posterior and lateral sidesurfaces, 113, 114, and 115, respectively, surround a generallycentrally located cavity 118 that forms a space for fusion material,such as a bone graft or bone graft substitute.

Interbody spacer 100 includes a recess 120 extending through anteriorsurface 113 inwardly toward cavity 118 and generally centered betweenthe superior 116 and inferior 117 surfaces. Recess 120 allows for thealignment of a congruent extension 1012 from either an instrument suchas an insertion instrument 1000, shown in FIG. 10, or an implantassembly such as plate assembly 1500, shown in FIG. 15. An aperture 119is centrally located within the recess 120 between the anterior surface113 and the cavity 118. The aperture 119 may be configured in either athreaded configuration, interference configuration or any means tosecure the interbody spacer 100 to a separate device.

FIG. 2 illustrates a top view of the interbody spacer 100 having agenerally oval shape. This shape is generated by rounding the anterior113, posterior 114, and lateral surfaces 115, as well as the cornersurfaces 211. The central opening 118 can be constructed by creating auniform offset of the outer perimeter 213. The interbody spacer 100benefits from a uniform geometry allowing the interbody to more evenlydistribute the load distribution on the vertebral endplates. The centerline A-P is defined by a line passing from the anterior surface 113 tothe posterior surface 114. The L-L line is defined by a line passingfrom the lateral surface 115 to the other lateral surface 115. The teeth112 are formed by adjacent ones of a plurality of anterior grooves 311(shown in FIG. 3) traversing longitudinally along the A-P direction anda plurality of lateral grooves 411 (shown in FIG. 4) traversingtransversely along the L-L direction. The intersection of anteriorgroove 311 and lateral groove 411 create a four sided pyramid-like tooththat maximize the surface area of superior surface 116 and inferiorsurface 117. While a four sided tooth is shown, those skilled in the artwill recognize that tooth (not shown) can have more or less than foursides. The teeth 112 are used to grip the superior and inferior endplateof the vertebral body (not shown).

FIG. 3 illustrates the interbody spacer 100 from the anterior directionand shows the recess 120 and aperture 119. The recess 120 is defined byparallel edge 312, which forms a line segment and can be used to blockrotation of congruent extension 1012 during insertion of the interbodyspacer 100 into a patient (not shown). The teeth 112 are defined by the“V” shaped anterior groove 311, however this groove can be a “U” shapedgroove, “L” shape groove, “O” shape groove or any other configuration ofgroove which is create by a low peak (or trough) 314, a high peak 315,and peak width 316.

FIG. 4 illustrated a side profile of an interbody spacer 100, which isshown as having a non-symmetric shape 400. The implant superior surface116′ and inferior surface 117′ cannot be mirrored about the A-P axis,thus defining the non-symmetric shape. The superior surface 117′ isdefined by a superior convex dome 412 in an anterior-posteriordirection, which is used to match the inferior vertebral endplate, notshown. The teeth 112 viewed from a lateral direction are constructedfrom an “L” shape groove 413 in the L-L direction. In order to maintainequal distance between peaks 315 on a domed surface, the teeth 112 mustrepeat at a crest angle (α), where crest angle α is greater than 0degrees. Exemplary values for crest angle α may be between about 0degrees and about 90 degrees. In an exemplary embodiment, crest angle αis about 10 degrees. The surfaces of adjacent peaks that define angle αextend generally perpendicular to the domed surface. The inferiorsurface 117′ teeth 112 are parallel to the A-P line and crest angle α isapproximately 0 degrees between high peaks 315.

FIG. 5 shows a posterior view of the interbody spacer 400, which showsthe overall wedge shaped. In an exemplary embodiment, the posteriorsurface 114 is a wedge shape to aid in the insertion of the interbodyspacer 100 into the vertebral disc space.

FIG. 6 shows the cross-sectional view of the interbody spacer 100 aswell as the recess 120, aperture 119 and a marker bore 612. The recess120 extends sufficiently into the interbody rigid body 111 enough tocreate a parallel edge 312. The aperture 119 extends from the recess 312into the central opening 118. Marker bore 612 generally is a cylindricalin shape, however this can be rectangular, triangular, or other suitableshape. Marker bore 612 is used to insert marker 1251 (shown in FIG. 12b), which can be constructed from any radiopaque material, such asstainless steel, titanium, tantalum, etc. Generally there are a total ofthree marker bores 612 and corresponding markers 1251 spaced along theperimeter of interbody spacer 100. The markers 1251, when viewed from ananterior direction, show the interbody spacer's 100 width, which isdefined from lateral surface 115 to opposing surface lateral surface115. The markers 1251 when viewed from the lateral position show thedepth of the implant. The depth is defined as the distance between theanterior surface 113 and the posterior surface 114.

FIGS. 7 and 8 show side views of an alternative embodiment of curvedsymmetric interbody spacer 700 and straight symmetric interbody spacer800, respectively, where the superior surface 116 and inferior surface117 are symmetric about the A-P line. In certain regions of the spine,such as lumbar or thoracic regions symmetrical interbody spacers 700 and800 may mate with the opposing vertebral endplates better than anon-symmetric interbody spacer 400. The symmetric interbodies 700 and800 are defined when the superior dome 412 or superior surface 116 canbe mirrored about the A-P centerline to be equivalent to the inferiordome 711 or inferior surface 117. Another feature that can aid theinsertion of the symmetric interbody spacer 700 and 800 in between thevertebral endplates is the width of rear crest 714. The width of rearcrest 714 is generally larger than the width of mid crest 716, whichallows for the interbody spacers 400, 700 and 800 to wedge itselfbetween the vertebral endplates. The rear crest 714 can be aided byaligning the superior 116 and inferior 117 surfaces at an angle 812 fromthe A-P centerline. In an exemplary embodiment, angle 812 can be betweenabout 0 degrees and about 90 degrees. In addition, the angle 812 can beused to match the spine curvature, such as Kyphosis or Lordosis angles.

FIG. 9 is a micrograph of a cross sectional cut of a substrate 910 andporous coating 912 on the surface of an interbody spacer 100, includingat least one side of each of the teeth 112. In an exemplary embodiment,the thickness of porous coating 912 can be between about 25 μm and about800 μm thick. The substrate 910 can be any polymeric material, such asPEEK, Polymethyl Methacrylate (PMMA), or any other biocompatible polymerwith a Young's modulus between about 0.1 GPa and about 50 GPa, which maybe used as the interbody spacer 100. The porous coating 912 isconstructed from an osteoconductive material, such as titanium, nickeltitanium, or any other material which may encourage bone in growth. Theporous coating 912 is rigidly bounded to substrate 910 through a bondedlayer 911, such as by a plasma spray, vapor deposition, or another othersurface additive method. The pores substrate 912 contains small to largesize cavities 914, which encourage bone in-growth and attachment. In anexemplary embodiment, the porosity of the pores substrate 912 can bebetween about 5 percent and about 80 percent porous. The interbodyspacer 100 superior dome 412 and superior surface 116 are coated withthe porous coating 912, as is the inferior dome 711 and inferiorsurfaces 117. The coating allows the interbody spacer rigid body 111 tomaintain the low stiffness, which can be constructed from PEEK or lowstiffness polymer, while gaining the porous coating 912 withosteoconductive properties.

Optionally, a hydroxyapatite coating can be applied on surfaces 113,114, 115 and on the walls of cavity 118 to enhance for visualization ofimplant 100 after implementation.

Another embodiment of the invention is the insertion instrument 1000illustrated in FIGS. 10-14, which is used to insert interbody 100 intothe spine. The insertion instrument 1000 must capture the interbodyspacer 100, position the interbody spacer 100, and deploy the interbodyspacer 100 in between two adjacent vertebral bodies (not shown). Theinsertion instrument 1000 has a handle 1010 used to grip the instrumentand rear end 1020 that can cooperate with an impact device (not shown).The hollow shaft 1016 is of a smaller diameter than the handle and hasenough length to maneuver around soft tissue. Located between the shaft1016 and handle 1010 has a cam 1018 used to engage and disengage a driveshaft 1252 from the aperture 119 in the interbody spacer 100. A fastenerportion, or engagement end 1014, is located at the opposite end from therear end 1020.

The engagement end 1014 is illustrated in FIGS. 11-12 b and is designedto releasably engage the interbody spacer 100. The engagement end 1014contains an engagement extension 1112, which is located at the end ofthe drive shaft 1252. The engagement extension 1112 is centrally locatedwithin the congruent extension 1012, which is defined by two paralleledges 1120. The congruent extension 1012 must contain at least oneparallel edge 1114 but can be in a circular, rectangular, hexagonal,triangular or oblong. The engagement end 1014 may also have depth stop1115, which is used to control the placement of the interbody spacer 100within the intervertebral disc space. The height of the depth stops 1115must be greater than the highest interbody spacer 100.

FIGS. 12-14 illustrate the attachment of the interbody spacer 100 to theinsertion instrument 1000. The interbody spacer 100 is positioned at theengagement end 1014 of the insertion instrument 1000. The engagementextension 1112 is coaxially aligned with and inserted into the implantaperture 119 in the recess 120 and the cam 1018 is rotated. The cam 1018translates rotational motion through the drive shaft 1252 and extendsengagement extension 1112, until engagement is achieved. In thisexample, the engagement extension 1112 and aperture 119 have matchingthreads, however engagement may also be completed by an interference fitor other suitable engagement means. The rotation of the cam 1018 drawsthe interbody spacer 100 until contact is achieved with depth stops1115. The interbody spacer 100 is then placed into position by using animpaction device (not shown), such as, for example, a mallet, a hammer,a slap hammer, or other such device, on the rear end 1020 until thedepth stops 1114 are flush with the surface of the vertebral bodies (notshown). The cam 1018 is then rotated in the reverse (unlocking)direction to retract engagement extension 1112 inwardly into shaft 1016in the direction of arrow “A” in FIG. 12 a, and the engagement extension1112 is then removed from interbody spacer 100. In the case of thenon-symmetric interbody spacer, alignments to the proper direction ofthe spine is important, as shown in FIG. 13. In this case, indicatorarrows 613 point towards the superior surface 116 and superior dome 412.During insertion, the surgeon needs to visualize these indicator arrows613 and the insertion instrument 1000 depth stop 1115 must have a width1310 small enough to visualize the arrows 613.

Another embodiment of the invention is a plate assembly 1500 illustratedin FIGS. 15-22. The plate assembly 1500 contains a rigid body 1508,which is defined by anterior surface 1510, posterior surface 1512, andan external perimeter 1518. The plate has a generally “dog bone” shapebut can have a rectangular, square or triangular shape. In an exemplaryembodiment, the plate 1500 includes at least two screw recesses 1520.Located in the center of the plate is a generally frusto-conicalcountersunk surface 1542 and attachment aperture 1540. The attachmentaperture 1540 is designed to align coaxially with the interbody spacer100 aperture 119 and has an equal or larger diameter than aperture 119.The countersunk surface 1542 and attachment aperture 1540 are coaxiallyaligned with the congruent extension 1012. The attachment aperture 1540is shown with a circular configuration but could be an oblong or ovalshape to allow linear translation of a locking screw 1810 (shown in FIG.18) relative to the plate 1500.

FIGS. 16-17 show a side view and bottom view of a congruent extension1012, respectively. The congruent extension 1012 is located on theposterior side 1512 of the plate assembly 1500 and is designed to engagewith a recess 120, such as the one contained on the interbody spacer100. The interbody spacer 100 is designed to sit in the center of plateassembly 1500. As such, the interbody 100 may be recessed beneath thevertebral walls. Therefore, the congruent extension 1012 sits on acongruent extension shelf 1720. The mating side of the congruentextension shelf 1720 matches the surface of the implant, such as theanterior surface 113 of the interbody spacer 100. In order to blockrotation of the plate 1500, the congruent extension 1012 contains atleast one straight portion 1722 that engages parallel edge 312, whichmay be incorporated into a circle, square, rectangle, triangle or oblongshape.

The congruent extension 1012 cooperatively engages the recess 112 of theinterbody spacer 100, as illustrated in FIGS. 18-20. Once the congruentextension 1012 is seated in the recess 120 of interbody spacer 100,locking screw 1810 can be used to secure the plate assembly 1500 to theinterbody 100. The locking screw 1810 generally has instrument recess1812 on the head 1912 and threads on the shaft 1910. The instrumentrecess 1812 is shown with a hexagonal connection but those skilled inthe art will recognize that the connection can be a Torx, Philips,Square or any other torque transmitting connection. The locking screw1810 has sufficient length for the trailing end 1914 to remain slightlyrecessed or extend in the central opening 118. In the example shown, theshaft 1910 is threaded into the aperture 119 in the interbody spacer100; however this can be an interference fit or any other fit in whichthe locking screw 1810 cannot disengage from the interbody spacer 100.

FIGS. 21 and 22 illustrate the attachment of bone screw 2100 to theplate assembly 1500 and interbody spacer 100. As shown in the Figures,when the plate 1500 is coupled to the intervertebral implant 100, afirst plurality of the recesses 1520 extends above the upper surface ofimplant 100 and a second plurality of recesses 1512 extends below thelower surface of the implant 100. The combination of the bone screws2100 in the plate assembly 1500 and interbody spacer 100 is to preventmotion post-operatively to enable the vertebral bodies to fuse to theporous coating 912 of interbody spacer 100 and achieve bone growththrough the central opening 118. Referring to FIG. 23, the bone screws2100 have a bulbous head 2110 and a head recess 2116 designed forengaging a mechanical translating instrument, such as a screw driver.The shaft 2118 is composed of a plurality of bone threads 2114 andterminate at a distal end 2112. The distal end 2112 is configured toself-drill and tap into the bone with the use of minimalinstrumentation.

The plate assembly 1500 screw recess 1520 is designed with a sphericalseat 2412 (shown in FIG. 24) to allow the bulbous head 2110 to seat in avariety of angular positions based of on an angle 2212 (shown in FIG.22) from the center axis 2214 of the plate assembly 1500. The angle 2212allows for the surgeon to customize the position of the bone screw 2100intraoperatively. The spherical like shape of the bulbous head 2110allows for the bone screws 1500 to adapt as the vertebral endplatessettle on the superior surface 116 and inferior surface 117 of theinterbody spacer 100. This plate configuration is known assemi-constrained; however the bone screw recess 1520 could be slotted toallow for linear dynamic transition of the bulbous head 2110.

Another embodiment of the invention is the locking head 2300 of bonescrew 2100 further illustrated in FIG. 23. The locking head 2300 iscomposed of a plurality of cantilever segments 2310 extending around thehead 2300 that are created when a circular groove 2314 is segmented by aplurality of gaps 2312 at equal distance from each other. In order forthe cantilever segments 2310 to deform, at least one gap 2312 must becreated between them. The groove 2314 is created circumferentiallyaround the axis 2320 of bone screw 2100 and extends outwards from thehead recess 2116.

FIGS. 24 and 25 show the bone screw 2100 inserted into a rigid platebody 1508 in an unlocked and locked position, respectively. The rigidbody 1508 screw recess 1520 is designed to have a spherical seat 2412,an undercut ledge 2520, and a cylindrical section 2522 extendinginwardly from the ledge 2520. The spherical seat 2412 is designed tocooperatively engage the bone screws bulbous head 2110 while allowingtranslation about the bone screw bore center axis 2214. The cantileversegments 2310 are designed to deflect, or bias, inwardly duringinsertion of the bone screw 2100 in the screw recess 1520 by contactingthe cylindrical section 2522 and deflecting towards the bone screw axis2320. The deflection is great enough to allow the bulbous head 2110 topass, but not enough to plastically deform the cantilever segments 2310.Once the bulbous head 2110 has passed the cylindrical section 2522 thecantilever segments 2310 elastically spring back, or bias outwardlybeneath cylindrical section 2522. The undercut ledge 2520 prevents thebone screws 2100 from disengaging from the plate 1508. The undercutledge 2520 also blocks excessive rotation of the bulbous head 2110 butcontacts the top of the cantilever segment 2310.

Another exemplary embodiment of the invention is a removable bodyextension assembly 2600 as illustrated in FIGS. 26-30. The removablebody extension assembly 2600 is a cylindrical shaped extension, whichcan be attached to a headless bone screw 2610, bone screw 2100, plate1500, or any other implantable implant requiring UDI tracking. Theremovable body extension assembly 2600 allows for indicia, ordescriptive information 2710, such as the part number 2714 and orserial/lot number 2716, to be contained with the implant, specifically,when the surface area, like the shaft 2616 of screw 2610, is not largeenough to contain the descriptive information 2710.

The removable body extension assembly 2600 has an engagement end 2810specifically designed to interface with an implant. In the example shownin FIG. 28, the engagement extension 2810 is threaded to engage recess3212 in the proximal head 2630 of a headless compression bone screw2610. The engagement extension 2810 can be press fit or have aninterference fit engagement recess 3212 or head recess 3210 of theimplant. The engagement extension 2810 may also be manufactured directlyas part of the implant in a monolithic configuration and disengagethrough breaking connection located at the engagement extension end2810.

In the case of the headless compression screw 2610, one issue duringsurgery is removing the headless compression screw 2610 from a screwholder because of the sharp proximal threads 2614 located on theproximal head 2630. The proximal end 2910 of the removable bodyextension 2600 can be smooth or knurled to allow a grip zone 2912. Priorto inserting headless compression screw 2610, the removable bodyextension 2900 is used to remove the screw from a screw caddie (notshown). The removable body extension 2900 is then removed by unscrewingthe engagement section 2810 from the engagement recess 3212 of screw2610. Screw 2610 is then inserted into the patient. The removable bodyextension 2900 is left outside of the patient and the descriptiveinformation 2710 is recorded.

In addition to headless bone screws, FIG. 30 shows an example of a plate1500 with the removable body extension 2900 attached via the engagementextension 2810. The removable body extension 2900 can be attached to anumber of implants, such as the interbody spacer 100, plate 1500,headless compression screw 2610, bone staple (not shown), suture anchor(not shown), or any other implant which is too small to physically lasermark descriptive information 2710.

In another embodiment shown in FIGS. 31-38, headless compression screw2610 is shown in more detail. The headless compression screw 2610 isdefined by proximal head 2630 and a distal end 2640 joined by a shaft2616. The distal end 2640 has distal threads 2612 with a distal pitch3310 and the proximal head 2630 has proximal threads 2614 with aproximal thread pitch 3312, where the proximal thread pitch 3312 is lessthan distal thread pitch 3310. The difference in proximal thread pitch3312 and distal thread pitch 3310 causes a compressive force to generatebetween segments. The proximal head 2630 has an engagement recess 3210which can be a Torx, Hexagonal, Square, or Phillips in shape.

FIGS. 36-38 specifically show the self-cutting features of the headlessbone screw 2620. The proximal head 2630 has a groove 3620, which removesmaterial as the proximal head 2630 and the proximal threads 2614 beginto engage a substrate, such as bone.

FIG. 37 illustrates a reverse cutting groove 3720 positioned on thedistal end 2640 and engages the distal threads 2612 near the shaft 2616.The reverse cutting groove 3720 removes material, such as bone, as theheadless bone screw 2610 is removed.

FIG. 38 illustrates the tip of the distal end 2640, which includesdistal threads 2612 and self drilling groove 3820. The length ofself-drilling groove 3820 is greater than the distal thread pitch 3310and is used as the headless bone screw 2610 is inserted into a substratesuch as bone.

Optionally, each device described above that is to be implanted (i.e.,interbody, screws, plate, etc.) can be coated with an antimicrobialagent, such as, for example, silver oxide. The anti-microbial coatingcan be in the form of a nano coating or other type of coating. Such anantimicrobial coating can be used to reduce or eliminate infectionswithin the patient.

It should also be understood that this invention is not limited to thedisclosed features and other similar method and system may be utilizedwithout departing from the spirit and the scope of the invention.

While the invention has been described with reference to the preferredembodiment and alternative embodiments, which embodiments have been setforth in considerable detail for the purposes of making a completedisclosure of the invention, such embodiments are merely exemplary andare not intended to be limiting or represent an exhaustive enumerationof all aspects of the invention. The scope of the invention, therefore,shall be defined solely by the claims. Further, it will be apparent tothose of skill in the art that numerous changes may be made in suchdetails without departing from the spirit and the principles of theinvention. It should be appreciated that the invention is capable ofbeing embodied in other forms without departing from its essentialcharacteristics.

What is claimed is:
 1. An orthopedic implant system comprising anintervertebral implant comprising a body having: an upper surfaceextending generally in a first plane, the upper surface having a firstplurality of longitudinal grooves and a second plurality of transversegrooves extending therealong, wherein portions of the upper surfaceextending between adjacent longitudinal grooves and transverse groovesform individual peaks; and a lower surface extending generally in asecond plane, oblique to the first plane, the lower surface having athird plurality of longitudinal grooves and a fourth plurality oftransverse grooves extending therealong, wherein portions of the lowersurface extending between adjacent longitudinal grooves and transversegrooves form individual peaks.
 2. The orthopedic implant systemaccording to claim 1, wherein each individual peak further comprises anosteoconductive material.
 3. The orthopedic implant system according toclaim 1, further comprising a side wall extending between the uppersurface and the lower surface, the side wall having an anterior portionand a posterior portion, each of the anterior portion and the posteriorportion having a radiopaque portion.
 4. The orthopedic implant systemaccording to claim 1, wherein the body has a generally centrally locatedcavity extending therethrough between the upper surface and the lowersurface.
 5. The orthopedic implant system according to claim 4, whereinthe body further comprises a side wall extending between the uppersurface and the lower surface, wherein the side wall further comprises arecess extending from the side wall inwardly toward the centrallylocated cavity and an implant aperture extending between the side walland the centrally located cavity.
 6. The orthopedic implant systemaccording to claim 5, wherein the recess is defined by at least onestraight line segment.
 7. The orthopedic implant system according toclaim 6, further comprising an insertion instrument releasably couplableto the intervertebral implant, the insertion instrument having afastener portion releasably couplable to the aperture, the insertioninstrument further having an extension portion, adjacent to the fastenerportion, the extension portion being releasably insertable into therecess.
 8. The orthopedic implant system according to claim 6, furthercomprising a generally planar plate couplable to the intervertebralimplant, the plate having an extension portion insertable into therecess, the extension portion having a generally straight portionadapted to engage the at least one straight line segment when theextension portion is inserted into the recess.
 9. The orthopedic implantsystem according to claim 8, wherein the plate further comprises aplurality of screw recesses extending therethrough such that, when theplate is coupled to the intervertebral implant, a first of the pluralityof recesses extends above the upper surface and a second of theplurality of recesses extends below the lower surface.
 10. Theorthopedic implant system according to claim 9, wherein each of theplurality of screw recesses comprises a cylindrical portion extendinginwardly therefrom.
 11. The orthopedic implant system according to claim10, further comprising a screw insertable into each of the plurality ofscrew recesses, each screw comprising: a screw head; and a plurality ofcantilever segments extending around the screw head, wherein, as eachscrew is inserted into its respective screw recess, the plurality ofcantilever segments engage the cylindrical portion and bias inwardlytoward the screw head and, after the cantilever segments pass thecylindrical portion, the cantilever segments bias outwardly away fromthe screw head underneath the cylindrical portion.
 12. The orthopedicimplant system according to claim 10, further comprising a screwinsertable into each of the plurality of screw recesses, each screwcomprising a shaft having a distal portion and a proximal portion,wherein the distal portion has a distal thread having a first pitch andthe proximal portion has a proximal thread having a second pitch, theproximal pitch being less than the distal pitch.
 13. The orthopedicimplant system according to claim 12, further comprising an implant bodyextension releasably couplable to the proximal portion of each screw,the implant body extension containing indicia imprinted thereon, theindicia providing identification information for the intervertebralimplant.
 14. The orthopedic implant system according to claim 8, furthercomprising an implant body extension releasably couplable to the plate,the implant body extension containing indicia imprinted thereon, theindicia providing identification information for the intervertebralimplant.
 15. The orthopedic implant system according to claim 8, whereinthe plate further comprises an attachment aperture extendingtherethrough such that the attachment aperture extends co-axially withthe implant aperture.
 16. An orthopedic implant system comprising: anintervertebral implant comprising a body having: an upper surface havinga generally convex shape in an anterior-posterior direction; a pluralityof upper peaks extending upwardly from the upper surface, each of theupper peaks having a side extending generally perpendicular to the uppersurface, wherein adjacent upper peaks in the anterior-posteriordirection have upper surfaces angled about 10 degrees with respect toeach other; a lower surface extending generally in a lower plane; and aplurality of lower peaks extending downwardly from the lower surface,each of the lower peaks having a side extending generally perpendicularto the lower surface, wherein adjacent lower peaks in theanterior-posterior direction have lower surfaces extending generallyparallel with respect to each other.
 17. The orthopedic implant systemaccording to claim 16, further comprising a plate releasably couplableto the body such that, when the plate is coupled to the body, the platehas a first screw recess extending above the upper peaks and a secondscrew recess extending below the peaks.
 18. The orthopedic implantsystem according to claim 17, further comprising: a screw insertablethrough each screw recess; and an implant body extension releasablycouplable to the proximal portion of each screw, the implant bodyextension containing indicia imprinted thereon, the indicia providingidentification information for the intervertebral implant.
 19. Theorthopedic implant system according to claim 16, further comprising aninsertion tool having a retractable engagement extension releasablyinsertable into the body between the upper surface and the lowersurface.
 20. An orthopedic implant system comprising: an intervertebralimplant comprising a body having: an upper surface; a first plurality ofupper peaks extending away from the upper surface, each of the upperpeaks having a plurality of sides extending generally away from theupper surface, wherein at least one of the sides has a porous coatingapplied thereto; a lower surface; and a second plurality of lower peaksextending away from the lower surface, each of the lower peaks having aplurality of sides extending away from the lower surface, wherein atleast one of the sides has a porous coating applied thereto.